Consumers' demands for smaller, cheaper, and faster electronic products directly affect packaging of integrated circuits. Integrated circuits have become an integral part of our daily live particularly in many portable electronic products such as cell phones, portable computers, voice recorders, etc. Integrated circuits are also in many larger electronic systems, such as cars, planes, industrial control systems, etc.
Increasing demand across virtually all aspects of modern life is driving improvements in integrated circuit technology. For essentially all applications, there continues to be demand for reducing cost, size, and increasing performance of electronic packages. Generally, an electronic package is defined as the case and interconnection for integrated circuits also referred to as ‘semiconductor device’, ‘chip’ or ‘die’.
The case and interconnection can form an electronic system that can provide interfacing and integration with a next level electronic system. The electronic package should provide a structure physically supporting the integrated circuit and protecting the integrated circuit from the environment, a means for removing heat generated by the integrated circuits or system, or electrical connections to provide signal and power access to and from the integrated circuit.
The integrated circuit is electrically connected to the electronic package through several technologies such as wire bonds, solder bumps, planar interconnect, tape connections, etc. One of the more mature and well-developed technologies is wire bonding. The maturity and extensive development contributes to typically lower cost including low cost materials and high yield for a large percentage of usable parts.
Wire bonding technology has been one of the most common techniques used to make electrical connections within the package. Wire bonding may employ gold, aluminum, or copper wires. A wire is typically bonded at one end to the integrated circuit and at the other end to a next-level system such as a substrate, a lead frame, a printed circuit board, a ceramic substrate, or a flexible circuit board.
The integrated circuit can include bond pads for the wire bonding connections. As market trends demand more functions in smaller form factors, packaging can require finer bond pad pitches or spacing, smaller bond pads, or bond pads limited to placement on only some edges of the integrated circuits.
The packages typically include a mounting and connection interface such as a leadframe, substrate, or interposer for electrical connections to the integrated circuit and a next level system such as a printed circuit board or another package. One of the most cost effective of the mounting and connection interfaces is the leadframe.
The leadframe is generally formed as a single unit including an integrated circuit mounting surface such as a die attach pad surrounded by connection strips such as lead fingers. The die attach pad is often a rectangle in the center of the leadframe with the lead fingers radiating from the die attach pad to allow connectivity around the outside edge.
Most commonly the integrated circuit is mounted to the die attach pad and connected to the lead fingers with wires. The die attach pad and lead fingers are held in place as a single unit during manufacturing. Prior to completion, the die attach pad and lead fingers are individually severed to provide electrically unique connections.
Forming the lead fingers around the outside edge of the die attach pad significantly limits the number of unique connections to the electronic package including the integrated circuit. As the demand continues to grow smaller, cheaper, and faster electronic products, manufacturers are seeking ways to cost effectively include more connections within a similar or smaller product size.
Thus, a need still remains for an integrated circuit package system to provide improved connectivity, pricing, and dimensions. In view of the increasing demand for improved integrated circuits and particularly more connections in smaller products at lower costs, it is increasingly critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.